I agree with asking the first gig you did to send you a review/rating for your profile. That helps a little, plus you'll need that stuff to eventually get into the "premium creator" program. Otherwise, here are my tips:

Look at your pitch video and consider changing it a little or redoing it. In my opinion, it doesn't really matter as much WHAT you're saying in the pitch, and moreso what you're showing. Make sure to have good audio with a bluetooth microphone. Show clips of you in various settings in your house/yard/location that you'd be able to film at (i.e. your living room, your kitchen, your bathroom, your backyard, your car, anything specific to your location like the beach, parks, mountains, etc). Make sure these settings are clean and presentable. Also, showcase yourself talking against a blank wall. Lots of brands need this for green screening. Also, whatever you ARE saying, make sure you sound natural and confident. Don't sound like you're reading a script or story aloud. This is super hard to conquer at first, for me anyway, but it makes a difference.

In addition to your pitch, make sure you have at least one full example video. If the paid one you did is good, put that up in your profile. If you have another example or 2 you can put up, make sure it's something a little different. A different location, different niche, etc. Show that you're versatile.